Pseudomonas spp. are organisms that are widespread and found commonly in water, soil and on plants. They are opportunistic pathogens and generally do not cause fatal diseases in healthy individuals. However, these organisms are responsible for considerable morbidity and mortality in patients whose normal defense mechanisms have been breached. Pseudomonads are of particular concern in hospitals because of their ability to survive in aqueous solutions such as disinfectants, irrigation fluids, and dialysis fluids. The species P. aeruginosa is implicated frequently in cases of nosocomial infection, and it is the most important human pathogen of its genera. P. aeruginosa is extremely adaptable and can survive in relatively hostile environments. Outside the hospital setting, it may be found in many moist environments, including sink traps, baths, hot tubs, swimming pools, cosmetics, and sneakers. The pathogenicity of this organism is attributed to the wide range of potent virulence factors that it produces, including proteases, exotoxins, endotoxins, and hemolysins. P. aeruginosa utilizes these virulence factors to cause a spectrum of diseases from superficial skin infections to acute bacterial sepsis. Diseases caused by P. aeruginosa are particularly difficult to treat because the organism is naturally resistant to most antibiotics. It has also been shown to develop additional antibiotic resistances after cessation of therapy, and untreatable strains are often isolated from patients with chronic lung infections (i.e. cystic fibrosis). Currently, the only available therapies for P. aeruginosa infections include fluoroquinolones, amikacin, gentamicin, and some of the newer broad-spectrum B-lactam antibiotics.
The frequency of Pseudomonas aeruginosa infections has risen dramatically in the past few decades. This has been attributed to the emergence of multiply antibiotic resistant strains and an increasing population of people with weakened immune systems. It is no longer uncommon to isolate Pseudomonas aeruginosa strains that are resistant to some or all of the standard antibiotics. This phenomenon has created an unmet medical need and demand for new anti-microbial agents, vaccines, drug screening methods, and diagnostic tests for this organism.
Moreover, the drug discovery process is currently undergoing a fundamental revolution as it embraces "functional genomics," that is, high throughput genome- or gene-based biology. This approach is rapidly superseding earlier approaches based on "positional cloning" and other methods. Functional genomics relies heavily on the various tools of bioinformatics to identify gene sequences of potential interest from the many molecular biology databases now available as well as from other sources. There is a continuing and significant need to identify and characterize further genes and other polynucleotides sequences and their related polypeptides, as targets for drug discovery.
Clearly, there exists a need for polynucleotides and polypeptides, such as the tktA embodiments of the invention, that have a present benefit of, among other things, being useful to screen compounds for antimicrobial activity. Such factors are also useful to determine their role in pathogenesis of infection, dysfunction and disease. There is also a need for identification and characterization of such factors and their antagonists and agonists to find ways to prevent, ameliorate or correct such infection, dysfunction and disease.